The present invention relates to devices and machines to process wound web material to form rolls. The invention especially relates to devices and machines to cut rolls made of paper, in particular tissue paper or similar cellulose products.
In the field of converting continuous web material, like paper or other cellulose-based materials, it is usually known to wind a web of indefinite length to form logs of high axial length, that are then cut into rolls of smaller axial length, destined to be packaged and distributed to end users. Examples of this kind of products are in the field of tissue paper, for instance rolls of toilet paper, kitchen towels and the like.
More specifically, rewinding machines produce logs of axial length equal to the length of the parent reel, from which the web material is unwound. The logs are then cut by means of saw machines, dividing each log into a plurality of rolls of smaller axial dimension equal to the dimension of the finished product.
The saw machines comprise one or more cutting blades, typically rotating disc blades or band blades. The blades act cyclically on one or more logs moving forward in advancing channels that are arranged adjacent to one another. At every cycle, the blade cuts one or more logs according to a cutting plane orthogonal to the axis of the logs. During cutting, the logs shall be held against the thrust of the blade, in a direction orthogonal to the axis of the log and thus to the feeding direction of the log in the advancing channel. To this end, clamp devices have been developed to clamp the logs laterally. U.S. Pat. No. 6,532,851, and other prior art documents cited therein, disclose an exemplary saw machine of the type described above.
The clamp devices to clap the logs laterally during cutting shall easily adapt to the diameter of the logs. To this end, various mechanisms have been developed to adapt the log clamp device. However, there is still a need to improve these devices, as regards both easiness of use and adjustment effectiveness and speed.